Tata Motors Ltd today announced that it has signed a joint development agreement with MAHLE for designing and developing a Secondary Loop Mobile Air Conditioning System (SL–MAC). This agreement was signed under the aegis of United Nations Environment, where the two companies, along with the Institute for Governance and Sustainable Development (IGSD) received funding for developing the SL-MAC system. IGSD is coordinating the project, which was funded by the Climate and Clean Air Coalition to Reduce Short-Lived Climate Pollutants (CCAC).
The companies noted that this project covers the use and trial of environment-friendly, low global warming potential (GWP) refrigerants HF01234yf (ASHRAE A2L) and HFC-152a (ASHRAE A2). A team comprising of representatives of the California Air Resources Board (CARB), Mobile Air Conditioning Society Worldwide (MACS), National Renewable Energy Lab (NREL), MAHLE, Tata Motors, and IGSD reviewed the newly constructed SL-MAC system. The team also inspected the prototype at the MAHLE Behr facility in Lockport, New York, USA, on 7 April 2017.
A Tata vehicle based on a new-generation platform for utility vehicles, consisting of a more complex architecture with front and rear air conditioning system, has been selected for this joint development program. The SL–MAC system will first be installed in the Tata utility vehicle as a prototype, the company said. Tata noted that the SL-MAC project is on schedule, with anticipated environmental and cost advantages to be determined in the next stages. The prototype will be tested on the Indian roads later in the third quarter of 2017, the company said.
The SL-MAC system functions in the way that the alternative refrigerants first cool a secondary fluid/coolant, which in turn cools the air to comfortable temperatures inside the vehicle cabin. This process allows the safe use of slightly flammable refrigerants that have low GWP, in turn achieving high cooling capacity, while minimising the losses and achieving an optimised overall thermodynamic efficiency. This is in contrast to the conventional mobile AC system, where the cabin air is directly cooled by the refrigerant HFC-134a, which is ozone safe but has a high GWP.
The new SL-MAC system is expected to increase vehicle energy efficiency through engineering. It will turn off the compressor during acceleration and retain coolness when the compressor is inactive or the engine is turned off for a short duration, allowing rapid cooling at restart. In addition to the expected energy efficiency benefits, the SL-MAC system allows the use of refrigerants that should avoid flow into the vehicle cabin, the company said. It added that the refrigerant never enters the passenger compartment and instead stays in the engine area, while only the coolant circulates through the interior air conditioning unit.
Dr Tim Leverton, Chief Technology Officer, Tata Motors, said as part of the company’s R&D efforts, it is committed to pioneering and inventing solutions to a greener future. Tata is the first OEM in India who is developing and evaluating an SL-MAC system on a car, using environmentally-friendly refrigerants, he added. The company is happy to work with class-leading global suppliers like MAHLE, and institutions like IGSD to contribute to the United Nations Environment initiative, noted Dr Leverton.
The Secondary Loop System will permit use of alternative refrigerants that have much lower GWPs than most currently used refrigerants, noted Dr Stephen O Andersen, PhD, Director of Research, IGSD. He said that the team will be comparing the life-cycle carbon footprint of HFC-152a to the carbon footprint of HFO-1234yf, and will estimate the cost of manufacture and ownership for each system.